Reducing power consumption has become an important issue for businesses because of environmental concerns and the rising costs of electricity. Corporations have made significant progress in reducing power consumption through employee education programs that encourage employees to turn off their lights and personal computers when they leave work each day. The success of this approach depends upon the diligence of employees in turning off lights, computers and other equipment when not in use. Some types of equipment take a long time to power up from a powered down state. For example, it is not uncommon for personal computers to require several minutes to “boot up.” Other types of equipment, such as copy machines and laboratory instruments, can require even more time to complete a power up cycle. These delays can have an adverse effect on productivity in situations where large numbers of employees are waiting for equipment to power up. As a result of these long delays, many employees leave equipment on all the time.
Another approach has been to configure certain types of equipment, such as personal computers, with a power saving mode of operation. A power saving mode is an operating mode in which a device consumes less power, typically by shutting down one or more subsystems. For example, personal computers typically shut down the hard disk and monitor in a power saving mode. A personal computer typically enters a power saving mode after a specified amount of time has passed without any keyboard or mouse activity. When keyboard or mouse activity resumes, power is restored to all components and the personal computer returns to the regular power state. One drawback of this approach is that the PC stills consumes power in the power saving mode, albeit at a reduced rate. Furthermore, the transition from power saving mode to regular operating mode can require several seconds or more, depending upon the particular implementation. Another drawback of this approach is that many older computers and other types of equipment are not configured with power saving modes of operation.
Based on the need to conserve power in buildings and the limitations in prior approaches, an approach for managing power consumption in buildings that does not suffer from the limitations of prior approaches is highly desirable.